lnd.xprv/chainntnfs/height_hint_cache.go
Wilmer Paulino f4cf1073d4
chainntnfs/height_hint_cache: prevent db transactions with no updates
In this commit, we modify our height hint cache to no longer start a
database transaction if no outpoints/txids are provided to update the
height hints for.
2018-10-30 17:59:31 -07:00

342 lines
8.8 KiB
Go

package chainntnfs
import (
"bytes"
"errors"
"github.com/btcsuite/btcd/chaincfg/chainhash"
"github.com/btcsuite/btcd/wire"
bolt "github.com/coreos/bbolt"
"github.com/lightningnetwork/lnd/channeldb"
)
const (
// dbName is the default name of the database storing the height hints.
dbName = "heighthint.db"
// dbFilePermission is the default permission of the database file
// storing the height hints.
dbFilePermission = 0600
)
var (
// spendHintBucket is the name of the bucket which houses the height
// hint for outpoints. Each height hint represents the earliest height
// at which its corresponding outpoint could have been spent within.
spendHintBucket = []byte("spend-hints")
// confirmHintBucket is the name of the bucket which houses the height
// hints for transactions. Each height hint represents the earliest
// height at which its corresponding transaction could have been
// confirmed within.
confirmHintBucket = []byte("confirm-hints")
// ErrCorruptedHeightHintCache indicates that the on-disk bucketing
// structure has altered since the height hint cache instance was
// initialized.
ErrCorruptedHeightHintCache = errors.New("height hint cache has been " +
"corrupted")
// ErrSpendHintNotFound is an error returned when a spend hint for an
// outpoint was not found.
ErrSpendHintNotFound = errors.New("spend hint not found")
// ErrConfirmHintNotFound is an error returned when a confirm hint for a
// transaction was not found.
ErrConfirmHintNotFound = errors.New("confirm hint not found")
)
// SpendHintCache is an interface whose duty is to cache spend hints for
// outpoints. A spend hint is defined as the earliest height in the chain at
// which an outpoint could have been spent within.
type SpendHintCache interface {
// CommitSpendHint commits a spend hint for the outpoints to the cache.
CommitSpendHint(height uint32, ops ...wire.OutPoint) error
// QuerySpendHint returns the latest spend hint for an outpoint.
// ErrSpendHintNotFound is returned if a spend hint does not exist
// within the cache for the outpoint.
QuerySpendHint(op wire.OutPoint) (uint32, error)
// PurgeSpendHint removes the spend hint for the outpoints from the
// cache.
PurgeSpendHint(ops ...wire.OutPoint) error
}
// ConfirmHintCache is an interface whose duty is to cache confirm hints for
// transactions. A confirm hint is defined as the earliest height in the chain
// at which a transaction could have been included in a block.
type ConfirmHintCache interface {
// CommitConfirmHint commits a confirm hint for the transactions to the
// cache.
CommitConfirmHint(height uint32, txids ...chainhash.Hash) error
// QueryConfirmHint returns the latest confirm hint for a transaction
// hash. ErrConfirmHintNotFound is returned if a confirm hint does not
// exist within the cache for the transaction hash.
QueryConfirmHint(txid chainhash.Hash) (uint32, error)
// PurgeConfirmHint removes the confirm hint for the transactions from
// the cache.
PurgeConfirmHint(txids ...chainhash.Hash) error
}
// HeightHintCache is an implementation of the SpendHintCache and
// ConfirmHintCache interfaces backed by a channeldb DB instance where the hints
// will be stored.
type HeightHintCache struct {
db *channeldb.DB
disabled bool
}
// Compile-time checks to ensure HeightHintCache satisfies the SpendHintCache
// and ConfirmHintCache interfaces.
var _ SpendHintCache = (*HeightHintCache)(nil)
var _ ConfirmHintCache = (*HeightHintCache)(nil)
// NewHeightHintCache returns a new height hint cache backed by a database.
func NewHeightHintCache(db *channeldb.DB, disable bool) (*HeightHintCache, error) {
cache := &HeightHintCache{
db: db,
disabled: disable,
}
if err := cache.initBuckets(); err != nil {
return nil, err
}
return cache, nil
}
// initBuckets ensures that the primary buckets used by the circuit are
// initialized so that we can assume their existence after startup.
func (c *HeightHintCache) initBuckets() error {
return c.db.Update(func(tx *bolt.Tx) error {
_, err := tx.CreateBucketIfNotExists(spendHintBucket)
if err != nil {
return err
}
_, err = tx.CreateBucketIfNotExists(confirmHintBucket)
return err
})
}
// CommitSpendHint commits a spend hint for the outpoints to the cache.
func (c *HeightHintCache) CommitSpendHint(height uint32, ops ...wire.OutPoint) error {
if c.disabled {
return nil
}
if len(ops) == 0 {
return nil
}
Log.Tracef("Updating spend hint to height %d for %v", height, ops)
return c.db.Batch(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
var hint bytes.Buffer
if err := channeldb.WriteElement(&hint, height); err != nil {
return err
}
for _, op := range ops {
var outpoint bytes.Buffer
err := channeldb.WriteElement(&outpoint, op)
if err != nil {
return err
}
err = spendHints.Put(outpoint.Bytes(), hint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// QuerySpendHint returns the latest spend hint for an outpoint.
// ErrSpendHintNotFound is returned if a spend hint does not exist within the
// cache for the outpoint.
func (c *HeightHintCache) QuerySpendHint(op wire.OutPoint) (uint32, error) {
if c.disabled {
return 0, ErrSpendHintNotFound
}
var hint uint32
err := c.db.View(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
var outpoint bytes.Buffer
if err := channeldb.WriteElement(&outpoint, op); err != nil {
return err
}
spendHint := spendHints.Get(outpoint.Bytes())
if spendHint == nil {
return ErrSpendHintNotFound
}
return channeldb.ReadElement(bytes.NewReader(spendHint), &hint)
})
if err != nil {
return 0, err
}
return hint, nil
}
// PurgeSpendHint removes the spend hint for the outpoints from the cache.
func (c *HeightHintCache) PurgeSpendHint(ops ...wire.OutPoint) error {
if c.disabled {
return nil
}
if len(ops) == 0 {
return nil
}
Log.Tracef("Removing spend hints for %v", ops)
return c.db.Batch(func(tx *bolt.Tx) error {
spendHints := tx.Bucket(spendHintBucket)
if spendHints == nil {
return ErrCorruptedHeightHintCache
}
for _, op := range ops {
var outpoint bytes.Buffer
err := channeldb.WriteElement(&outpoint, op)
if err != nil {
return err
}
err = spendHints.Delete(outpoint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// CommitConfirmHint commits a confirm hint for the transactions to the cache.
func (c *HeightHintCache) CommitConfirmHint(height uint32, txids ...chainhash.Hash) error {
if c.disabled {
return nil
}
if len(txids) == 0 {
return nil
}
Log.Tracef("Updating confirm hints to height %d for %v", height, txids)
return c.db.Batch(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
var hint bytes.Buffer
if err := channeldb.WriteElement(&hint, height); err != nil {
return err
}
for _, txid := range txids {
var txHash bytes.Buffer
err := channeldb.WriteElement(&txHash, txid)
if err != nil {
return err
}
err = confirmHints.Put(txHash.Bytes(), hint.Bytes())
if err != nil {
return err
}
}
return nil
})
}
// QueryConfirmHint returns the latest confirm hint for a transaction hash.
// ErrConfirmHintNotFound is returned if a confirm hint does not exist within
// the cache for the transaction hash.
func (c *HeightHintCache) QueryConfirmHint(txid chainhash.Hash) (uint32, error) {
if c.disabled {
return 0, ErrConfirmHintNotFound
}
var hint uint32
err := c.db.View(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
var txHash bytes.Buffer
if err := channeldb.WriteElement(&txHash, txid); err != nil {
return err
}
confirmHint := confirmHints.Get(txHash.Bytes())
if confirmHint == nil {
return ErrConfirmHintNotFound
}
return channeldb.ReadElement(bytes.NewReader(confirmHint), &hint)
})
if err != nil {
return 0, err
}
return hint, nil
}
// PurgeConfirmHint removes the confirm hint for the transactions from the
// cache.
func (c *HeightHintCache) PurgeConfirmHint(txids ...chainhash.Hash) error {
if c.disabled {
return nil
}
if len(txids) == 0 {
return nil
}
Log.Tracef("Removing confirm hints for %v", txids)
return c.db.Batch(func(tx *bolt.Tx) error {
confirmHints := tx.Bucket(confirmHintBucket)
if confirmHints == nil {
return ErrCorruptedHeightHintCache
}
for _, txid := range txids {
var txHash bytes.Buffer
err := channeldb.WriteElement(&txHash, txid)
if err != nil {
return err
}
err = confirmHints.Delete(txHash.Bytes())
if err != nil {
return err
}
}
return nil
})
}